Burner



Sept. 22, 1970 SHOICHI TSUJI ET AL 3,529,915

BURNER I Filed June 6, 1968 2 Sheets-Sheet l 'INVENTORS SHOICHI rsuzn KIYOSHI AOKI TAKESH! SAKAI ATTORNEYS Sept.- 22, 1970 SHOICHI TSUJI T BURNER 2 Sheets-Sheet 2 Filed June 6, 1968 mvE NTORS SHOICH TSUJ'I KIYOSHI AOKI TAKESHI SAKAI ATTORNEYS United States Patent O 3,529,915 BURNER Shoichi Tsuji, Toyko-to, Kiyoshi Aoki, Chiba-shi, and

Takeshi Sakai, Tokyo-t0, Japan, assignors to Ishikawajima-Harima Jukogyo Kabushiki Kaisha, Tokyo-t0, Japan, a company of Japan Filed June 6, 1968, Ser. No. 735,086 Claims priority, application Japan, June 9, 1967, 42/ 49,118; Dec. 20, 1967, 42/106,736 (utility models) Int. Cl. F23g 9/00 US. Cl. 431284 1 Claim ABSTRACT OF THE DISCLOSURE A burner for gas or liquid fuel which comprises a larger nozzle provided in the center of the burner disk and a suitable number of nozzles provided on the circumference of a concentric circle encircling the said a larger nozzle, the quantities of fuel injected from both nozzles being so adjusted as to vary the length of the flames and temperature distribution.

DETAILED EXPLANATION OF THE INVENTION This invention relates to an improved burner for gas or liquid fuel.

In a furnace for heating steel, a furnace for purification of petroleum or for other petro-chemical purposes or a boiler for generating steam, incorporating a burner for gas or liquid fuel, it may become necessary to vary the length of the flame and the temperature distribution of the flame when there is a change in operating conditions, such as a change in the load or in the type of the fuel gas.

In the conventional gas burners, such adjustment is generally done by altering the mixing ratio of the primary air to the fuel gas. However, such adjustment system permits an adjustment of the length of the flame and the temperature distribution only in a very narrow range and furthermore involves a risk of a backfire into the nozzle while making such adjustment. This means that the construction of the conventional gas burners are not suitable for such adjustment.

On the other hand, if a burner used is a general liquid fuel burner, the length of the flame may be varied by altering the swirling force of the combustion air thereto or by changing the flow quantity of the atomizing steam jet. In this case, however, there may arise such trouble as unstable or incomplete combustion due to such adjustment the flow speed of the fuel in the flame and its fuel concen tration distribution diverge from the optimum combustion conditions when the length of the flame is excessively long or short with the result that the adjustment range is too limited in the conventional liquid fuel burners to efficiently cope with the said changes in operating conditions.

An object of this invention therefore is to provide an improved gas or liquid fuel burner in which the length of the flame and the temperature distribution can be varied in a wider range and at the same time such risk as that of a backfire can be eliminated.

A preferred embodiment of this invention is described below in reference to the accompanying drawings.

FIG. 1 illustrates a longitudinal section of a gas burner according to this invention. FIG. 2 is its front view at line A-A. FIG. 3 is a longitudinal section of a liquid fuel burner according to this invention. And FIG. 4 is its front view at line B-B.

In FIGS. 1 and 2, the reference numeral 1 shows the main body of the burner, 2 is a burner disk, 3 an air reservoir, 4 its air inlet, 5 a nozzle having a larger diameter provided in the center of the burner disk 2, 6 pilot combustion holes consisting of a plurality of small holes provided on the circumference of the inner concentric circle encircling this nozzle, 7 a plurality of combustion holes provided on the circumference of the outer concentric circle, 8 a primary fuel pipe extending through the main body 1 of the burner from behind and connected to the nozzle 5 by its mouth piece 9, 10 a pinhole gas nozzle provided in the mouth piece 9 and opened in the pilot combustion holes 6, 11 a secondary fuel pipe surrounding the primary fuel pipe 8 the secondary fuel pipe having radial branches in the air reservoir 3, and the gas nozzles 13 of each such branch 12 being opened in each of the combustion holes 7 but having a smaller diameter than that of the said nozzle 5.

In the same figures, 14 is a valve provided in the connecting pipe 8' for the primary fuel pipe 8 and 15 is a valve provided in the connecting pipe 11 for the secondary fuel pipe 11. v

To describe the mechanism of the operation of the aforementioned apparatus, the fuel gas is jetted out from the nozzle 5 having a larger diameter through the primary fuel pipe 8, the fuel gas of the secondary fuel pipe 11 is jetted out, partially mixed with air, from each combustion hole through the branch 12 and the gas nozzle 13, the flame from the nozzle 5 is stabilized by the pilot flame from the pilot combustion holes 6 and the flow quantities of the primary and secondary fuel gases are controlled by means of the valves 14, 15.

If the valve 14 only is opened to burner the primary fuel gas, an extremely long flame can be obtained because the nozzle 5 has a large diameter and is provided at a distance from the combustion hole 7 (in this case, only the air is jetted out).

If the valve 15 only is opened to burn the secondary fuel gas, an extremely short flame is obtainable since the gas nozzle 13 has a small diameter and the gas from it is injected from the combustion hole 7 together with the air. Therefore, if the ratio of the flow quantities between the primary and secondary fuel gases: is adjusted by means of the respective valves 14, 15, the length of the flame can be freely varied within the range of the longest flame by the nozzle 5 only and the shortest flame by the combus tion holes 7 only.

As regards the temperature distribution of each flame of the primary and secondary fuel gases, it is easily understandable that the temperature of the flame from the nozzle 5 is highest near the middle of its length, and the temperature of the flame from the combustion hole 7 is highest near the hole whereas it decreases as the distance from the hole becomes greater. For this reason, the temperature distribution can be likewise adjusted as desired by adjusting the flow quantities of the primary and secondary fuel gases as in the cases of adjusting the flame length. Thus, a wide-range adjustment of the flame length and its temperature distribution can be accomplished.

A preferred embodiment of a liquid fuel burner according to this invention is shown in and described in reference to FIGS. 3 and 4. In FIGS. 3 and 4 having the numbers corresponding to those used in FIGS. 1 and 2, 16 is a primary atomizing nozzle with a large capacity provided adjacent to a pirmary combustion hole 16', 17 a secondary combustion hole provided on the circumference of a concentric circle surrounding the primary combustion hole 16' and communicating with the said air reservoir 3, 18 a secondary atomizing nozzle with a small capacity provided in the center of the secondary combustion hole with a fixed space between it and the inner periphery of the said secondary combustion holes, 19 a primary fuel pipe extending to the rear of the main body 1 of the burner, 20 a valve mounted in the primary fuel pipe 19, 21 a secondary fuel pipe branched from the main secondary fuel pipe 22 mounted behind the main body 3 of the burner and extending to each of the secondary atomizing nozzles 18, 23 a valve mounted in the main pipe 22, which valve is used to adjust the amount of the fuel emitted from the secondary atomizing nozzle 18 while the amount of the fuel jetted out from the primary atomizing nozzle 16 is adjusted by the valve 20.

If the valve 20 only is opened to burn the primary fuel, a very long flame is produced because a large amount of fuel is emitted from the primary atomizing nozzle 16 and because it takes time for the atomized fuel to mix with the air since the primary combustion hole 16 and the secondary combustion hole 17 supplying the air thereto are provided with a sufficient space between them.

If the valve 23 only is opened to burn the secondary fuel, an extremely short flame is obtained because the quantity injected from each secondary atomizing nozzle 18 is small and because the fuel is mixed with the air quite satisfactorily since the second combustion hole 17 is connected to the air reservoir 3. Consequently, the length of the flame can be freely varied by adjusting the ratio of the flow quantities between the primary and secondary fuels by means of the valves 20 and 23.

And, as for the temperature distribution of each flame from the primary combustion hole 16' and the secondary combustion holes 17, the temperature of the former is highest near the middle of its length, and the temperature of the latter is highest near the combustion hole While it decreases as the distance from the combustion hole becomes greater. Thus, the temperature distribution can be freely altered as desired by adjusting the said valves 20 and 23.

As is clear from the above description, in the gas burner according to this invention, the length of the flame and the temperature distribution can be freely varied in a wide range of cope with any such change in operating condition as first above mentioned and, moreover, such adjustment can be very easily made by simply adjusting the flow quantities of the primary and secondary fuel gases by means of the respective valves, eliminating any such risk as a backfire. In the liquid fuel burner of this invention, a wide range adjustment of the flame length and the temperature distribution can be most easily made by simply adjusting the valves on the primary and secondary sides. In addition to the aforementioned features, the burner according to the present invention has the advantages that its structure is so simple and the combustion efficiency is extremely high, thereby assuring a wide scope of application.

What is claimed is:

1. A gas or liquid fuel burner comprising a main body having an internal air reservoir, a burner disc mounted on the main body and having an unobstructed external face, a nozzle passing through the disc and defining an opening in the center of the face, a plurality of combustion holes directly communicating with the air reservoir and opening on the face in an arrangement of equal spacing on a circle concentric with and surrounding the nozzle opening, a primary fuel pipe passing through the air reservoir and having a free end communicating with the nozzle, the free end being aligned concentrically with the nozzle and blocking direct communication between the air reservoir and the nozzle, a secondary fuel pipe having a plurality of branches passing through the air reservoir, each of said branches having a free end communicating with and concentrically arranged within a respective one of the combustion holes, the free end of each of said branches being of smaller diameter than the corresponding combustion hole, and valve means for adjusting the ratio of the quantity flow rate of fuel through the primary fuel pipe to the quantity flow rate of fuel through the secondary fuel pipe.

References Cited UNITED STATES PATENTS 2,935,128 5/1960 Ferguson 431-284 3,163,203 12/1964 Ihlenfield 431-284 3,273,621 9/1966 Childree 431-284 EDWARD G. FAVORS, Primary Examiner 

